Phases of clinical researchThe phases of clinical research are the stages in which scientists conduct experiments with a health intervention to obtain sufficient evidence for a process considered effective as a medical treatment. For drug development, the clinical phases start with testing for drug safety in a few human subjects, then expand to many study participants (potentially tens of thousands) to determine if the treatment is effective. Clinical research is conducted on drug candidates, vaccine candidates, new medical devices, and new diagnostic assays.
Contrast agentA contrast agent (or contrast medium) is a substance used to increase the contrast of structures or fluids within the body in medical imaging. Contrast agents absorb or alter external electromagnetism or ultrasound, which is different from radiopharmaceuticals, which emit radiation themselves. In x-ray imaging, contrast agents enhance the radiodensity in a target tissue or structure. In magnetic resonance imaging, contrast agents shorten (or in some instances increase) the relaxation times of nuclei within body tissues in order to alter the contrast in the image.
Zinc sulfateZinc sulfate describes a family of inorganic compounds with the formula ZnSO4(H2O)x. All are colorless solids. The most common form includes water of crystallization as the heptahydrate, with the formula . It was historically known as "white vitriol". Zinc sulfate and its hydrates are colourless solids. The main application of the heptahydrate is as a coagulant in the production of rayon. It is also a precursor to the pigment lithopone. It is also used as an electrolyte for zinc electroplating, as a mordant in dyeing, and as a preservative for skins and leather.
Aggregate demandIn macroeconomics, aggregate demand (AD) or domestic final demand (DFD) is the total demand for final goods and services in an economy at a given time. It is often called effective demand, though at other times this term is distinguished. This is the demand for the gross domestic product of a country. It specifies the amount of goods and services that will be purchased at all possible price levels. Consumer spending, investment, corporate and government expenditure, and net exports make up the aggregate demand.
Electric fieldAn electric field (sometimes E-field) is the physical field that surrounds electrically charged particles and exerts force on all other charged particles in the field, either attracting or repelling them. It also refers to the physical field for a system of charged particles. Electric fields originate from electric charges and time-varying electric currents. Electric fields and magnetic fields are both manifestations of the electromagnetic field, one of the four fundamental interactions (also called forces) of nature.
Chemical potentialIn thermodynamics, the chemical potential of a species is the energy that can be absorbed or released due to a change of the particle number of the given species, e.g. in a chemical reaction or phase transition. The chemical potential of a species in a mixture is defined as the rate of change of free energy of a thermodynamic system with respect to the change in the number of atoms or molecules of the species that are added to the system.
Radiocontrast agentRadiocontrast agents are substances used to enhance the visibility of internal structures in X-ray-based imaging techniques such as computed tomography (contrast CT), projectional radiography, and fluoroscopy. Radiocontrast agents are typically iodine, or more rarely barium sulfate. The contrast agents absorb external X-rays, resulting in decreased exposure on the X-ray detector. This is different from radiopharmaceuticals used in nuclear medicine which emit radiation.
Active ingredientAn active ingredient is any ingredient that provides biologically active or other direct effect in the diagnosis, cure, mitigation, treatment, or prevention of disease or to affect the structure or any function of the body of humans or animals. The similar terms active pharmaceutical ingredient (abbreviated as API) and bulk active are also used in medicine. The term active substance may be used for natural products. Some medication products can contain more than one active ingredient.
Zinc oxideZinc oxide is an inorganic compound with the formula ZnO. It is a white powder that is insoluble in water. ZnO is used as an additive in numerous materials and products including cosmetics, food supplements, rubbers, plastics, ceramics, glass, cement, lubricants, paints, sunscreens, ointments, adhesives, sealants, pigments, foods, batteries, ferrites, fire retardants, semi conductors, and first-aid tapes. Although it occurs naturally as the mineral zincite, most zinc oxide is produced synthetically.
Good clinical practiceGood clinical practice (GCP) is an international quality standard, which governments can then transpose into regulations for clinical trials involving human subjects. GCP follows the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH), and enforces tight guidelines on ethical aspects of clinical research. High standards are required in terms of comprehensive documentation for the clinical protocol, record keeping, training, and facilities, including computers and software.
Aggregate supplyIn economics, aggregate supply (AS) or domestic final supply (DFS) is the total supply of goods and services that firms in a national economy plan on selling during a specific time period. It is the total amount of goods and services that firms are willing and able to sell at a given price level in an economy. There are two main reasons why the amount of aggregate output supplied might rise as price level P rises, i.e., why the AS curve is upward sloping: The short-run AS curve is drawn given some nominal variables such as the nominal wage rate, which is assumed fixed in the short run.
Magnetic fieldA magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular to its own velocity and to the magnetic field. A permanent magnet's magnetic field pulls on ferromagnetic materials such as iron, and attracts or repels other magnets.
